On Tue, May 31, 2016 at 4:34 PM, David Fetter <da...@fetter.org> wrote:
> While querying some JSONB blobs at work in preparation for a massive
> rework of the data infrastructure, I ran into things that really
> puzzled me, to wit:
> SELECT * FROM unnest('["a","b","c"]'::jsonb);
> ERROR: function unnest(jsonb) does not exist
> SELECT * FROM jsonb_array_elements('["a","b","c"]'::jsonb);
> (3 rows)
I'd be inclined to -1 such a proposal. TIMTOWTDI is not a principle that
we endeavor to emulate.
Having an overloaded form: <unnest(jsonb) : setof jsonb> is unappealing.
While likely not that common the introduction of an ambiguity makes raises
the bar considerably.
That said we do seem to be lacking any easy way to take a json array and
attempt to convert it directly into a PostgreSQL array. Just a conversion
is not always going to succeed though the capability seems worthwhile if as
yet unasked for. The each->convert->array_agg pattern works but is likely
inefficient for homogeneous json array cases.